Lifted Pads on a PCB after wave soldering for PTH boards

Generally pads are small round or square areas of copper which are normally used to make a connection to a component pin. If these pads are not sitting correctly or are lifted, it can cause the connection between the printed circuit board (PCB) and the component to fail.

Pad lifting on printed circuit boards during the assembly process is typically caused by a combination of a thermal and physical issue.

Lifted pads are rarely seen on PTH (plated through hole) boards but can occur on single-sided boards during assembly. The example in Figure 1 occurred directly after wave soldering when the assembly was being handled. The adhesion of the copper foil decreases as the surface heats up so directly after soldering the copper adhesion can be low. Any handling or force applied to the components can cause lifting of the pads. Care needs to be taken when lifting boards from the conveyor or out of pallets as often large components are often used by operators as handles.

Figure 1- This lifted pad occurred during handling, right after wave soldering.